1. Related Technical Fields
Related technical fields include map information delivery systems and, in particular, map information delivery system which deliver updating information for updating the map information from a map information delivery center to a navigation apparatus.
2. Related Art
Navigation apparatuses are increasingly being installed in vehicles. Such a navigation apparatus is structured to detect a current position of a vehicle using a GPS receiver. The apparatus to obtains map data corresponding to the current position from a recording medium such as a DVD-ROM and HDD, or a network. Then, the apparatus displays the obtained map data on a liquid crystal monitor. The obtained map data, which contains the current position of the vehicle, is loaded from the recording medium to form a map image showing an area around the current position of the vehicle on a display unit. A vehicle position mark may be superimposed on the map image and the map image may be scrolled as the vehicle travels. The position mark also allows the driver to easily identify the vehicle position on the map image.
As roads are newly built every year, old roads are closed, or the configuration of the existing road is changed. It is therefore necessary to update the map data stored in the navigation apparatus at a predetermined time interval. Updating of the map data is performed by replacing an old DVD with a newly purchased DVD, writing the map data into the HDD in a shop, and/or rewriting the contents of the HDD based on the map data delivered from a map information delivery center.
Japanese Patent Application Publication No. JP-A-2000-180187 (paragraphs [0014] to [0098], FIGS. 1 to 18) discloses a map information delivery system including a map information delivery center and a navigation apparatus. The navigation apparatus may include a control unit for displaying on a display unit reception data received from the map information delivery center via wireless communication. The navigation apparatus may include a memory unit that stores map information and/or identification information of available map information, and a detection unit that detects a current position of the host vehicle and a traveling direction of the host vehicle. The control unit automatically receives the map information during the wireless communication with the map information delivery center, and thereby updates or adds to the map information stored in the memory unit. The navigation apparatus allocates priorities to the map information near the current position of the host vehicle detected by the detection unit, the map information with the detailed scale, the map information with the same scale as that of the map currently displayed on the display, the map information showing the area in the traveling direction of the host vehicle detected by the detection unit, and the map information capable of updating the oldest map information stored in the memory unit, in that order. The map information is required in the aforementioned priority order.